Just take a look at the problems reported on the forums (and these mailing lists). Take a look at the bugs - here, here and here… oh and this is my bug, affecting nearly every machine in my office - which (unsurprisingly), I base on nVidia + AMD.
nVidia has been our choice for a long time because of its superb driver support on Linux. Lucid 10.04 is a 3 years supported version and one which is going to stay for a long time in the corporate environment.
Everyone is having a screwed up time with nvidia on 10.04 - especially the older nvidia chips (which are still very popular today, integrated into motherboards). I’m not sure who is to blame… but you dont want to upset some of your most vocal fanbase, who are incidentally more influential in the workplace than your typical gamer fanboy.